Someone told me that put and brush the toothpaste on the pearl's skin and the skin can be as bright as the new one. However, it is not an ideal way to do so.

The toothpaste contains a high micro-hardness abrasive particulate matter, which is particularly small and hard(almost as hard as crystal). That's to say, the method of cleaning jewelry by toothpaste will damage the surface which hardness is lower than crystal, such as the surface of pearl, gold and K gold.

The correct cleaning solution should use the neutral-active agent(such as baby shampoo). I had made a detailed introduction about it in previous article How to Recover Pearl's Nature Gloss.